The invention relates to a centrifuge which has the following: A centrifugal drum, a supply pipe which leads into the centrifugal drum for introducing a material for the centrifugal process into the centrifugal drum, and a supply duct for supplying a control fluid into an opening and/or closing section of the centrifugal drum. The invention also relates to a method of operating a centrifuge according to the invention.
A centrifuge of this type is known from German Patent Document DE 28 22 478. The centrifuge illustrated in that document has a centrifugal drum with a sleeve valve to which a chamber is assigned which is connected by ducts in a spindle with a hydraulic system. The introduction of the product takes place from above by way of a central supply pipe. The spindle is situated on the underside of the centrifugal drum. Although this construction has been found to be successful per se, it reaches its limits when, for hygiene reasons, the product area is to be situated separately from the driving area of the centrifuge and the control elements of the drive as well as the control elements of the control fluid supply outside the drum (valves, etc.).
From German Patent Document DE-A-2808677, the use of a gaseous medium as control fluid is known, the supply duct being concentrically to the supply pipe for the process material.
A centrifuge of the above-mentioned type is known from U.S. Pat. No. 4,044,945. However, this construction does not ensure that, for reasons of hygiene, the product area is situated separate from the driving area of the centrifuge and the control elements of the drive as well as the control elements of the control fluid supply outside the drum (valves, etc.).
The object of the invention consists of further developing the centrifuge of the above-mentioned type such that a gaseous medium can be used as a control fluid in order to permit an uncomplicated handling and the use under sterile conditions.
The invention achieves this goal because the control fluid supply and the material supply are thus jointly guided into the centrifugal drum and preferably extend also directly side-by-side, a constructively separate supply of the control fluid can be avoided.
The invention is particularly suitable for a centrifuge wherein the centrifugal drum hangs on a centrifuge frame, the supply pipe for the process material and the supply duct for the control fluid extend jointly from above into the centrifugal drum. In the case of centrifuges with hanging centrifugal drums, a separate feeding of the control fluid from below into the drum is not practical because it may be necessary to collect the solids separated in the separation process below the drum in a sterile container. This is clearly simplified by the control fluid supply xe2x80x9cfrom abovexe2x80x9d.
A double-walled pipe has the advantage of a particularly space-saving housing of the control fluid supply and of the process material supply.
In this case, the control fluid supply is used for operating a displaceable sleeve valve for opening and closing discharge openings for solids in the centrifugal drum. In this case, an opening chamber and a closing chamber adjoin the sleeve valve. The sleeve valve is moved by the admission of pressure by means of the control fluid, in which case it is also possible to hold the sleeve valve in a spring-tensioned manner in one of its operating positions and move it into the respective other operating position by a pressure buildup in the corresponding control chamber.
In this case, a gaseous medium, preferably sterile air, is used as the control fluid, which can be handled in an uncomplicated manner and is well suited for a use as a control medium under sterile conditions, because, also in the event of a direct contact with the process material, a contamination of the latter will be prevented.